Not even Lord Tenma's sex, looks, or personality is known, so all images are speculative.
The only thing known is that (s)he lives on Youkai Mountain and is the boss of all tengu, including the Daitengu (management), Crow Tengu (information), Hanataka Tengu (office), White Wolf Tengu (defense), and Yamabushi Tengu (printing). Shameimaru Aya, Himekaidou Hatate, and Inubashiri Momiji all work under him/her.